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%I #16 Sep 08 2022 08:45:56
%S 2,6,8,12,14,18,20,24,26,30,32,36,38,42,44,48,50,54,58,60,64,66,70,72,
%T 76,78,82,84,88,90,94,96,100,102,106,110,112,116,118,122,124,128,130,
%U 134,136,140,142,146,148,152,154,158,160,164,168,170,174,176,180,182,186,188,192,194,198,200,204,206,210,212,216,220,222,226,228,232,234,238,240
%N a(n) = n + [n*r/t] + [n*s/t]; r=1, s=(sin(Pi/5))^2, t=(cos(Pi/5))^2.
%H G. C. Greubel, <a href="/A189933/b189933.txt">Table of n, a(n) for n = 1..10000</a>
%F From _G. C. Greubel_, Jan 13 2018: (Start)
%F A005408: a(n) = n + [n*(sin(Pi/5))^2] + [n*(cos(Pi/5))^2] = 2*n - 1.
%F A189932: b(n) = n + [n*(csc(Pi/5))^2] + [n*(cot(Pi/5))^2].
%F A189933: c(n) = n + [n*(sec(Pi/5))^2] + [n*(tan(Pi/5))^2]. (End)
%t With[{s=Sin[Pi/5]^2,t=Cos[Pi/5]^2},Table[n+Floor[n/t]+Floor[(n*s)/t],{n,80}]] (* _Harvey P. Dale_, Feb 22 2013 *)
%o (PARI) for(n=1,100, print1(n + floor(n/(cos(Pi/5))^2) + floor(n*(tan(Pi/5))^2), ", ")) \\ _G. C. Greubel_, Jan 13 2018
%o (Magma) C<i> := ComplexField(); [n + Floor(n/(Cos(Pi(C)/5))^2) + Floor(n*(Tan(Pi(C)/5))^2): n in [1..100]]; // _G. C. Greubel_, Jan 13 2018
%Y Cf. A189932, A189935.
%K nonn
%O 1,1
%A _Clark Kimberling_, May 01 2011
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